This is sort of the defining mechanic of these games in my memory. The first thing that pops into my head when I think of Last Ninja is aligning and realigning myself, and squatting, awkwardly and repeatedly (just like a real ninja, lol), until that satisfying new item icon appears. Perhaps surprisingly, these are very fond memories.

This mechanic is augmented by not even always knowing which graphics in the environment can be picked up, or by invisible items that are inside boxes or otherwise out of sight (I think LN2 had something in a bathroom? You have to position yourself in the doorway and do a squat of faith).

The other core memory is the spots that require a similarly awkward precision while jumping. These are worse, because each failure loses you one of your limited lives. The combat is also finicky. I remember if you come into a fight misaligned, your opponent might quickly drain your energy while you fail to get a hit in.

At the time, it seemed appropriate to me that it required such a difficult precision to be a ninja. I was also a kid, who approached every game non-critically, assuming each game was exactly as it was meant to be. Thus I absolutely loved it, lol.

joysticks only had one fire button.